I am curious about the material of stainless in chimneys of the big box stores vs the distributors/dealersbrands. In some cases the brands are the same ie; Simpson Duravent. I am lead to believe the product in the big box stores is not of the same materials such as thickness. One distributor claims they offer 25% thicker stainless. I tried to find out the detailed specifications but this is apparently a guarded secret. Any knowing details is appreciated. Thanks